Thai Longtail Mud Motors: Boat Width + Engine Size + Shaft Length

All about Thai longtail mud motors. Best boat width, engine size, and shaft length. Let’s get into it!

Thai Longtail Mud Motors

There are a couple of Thai longtail mud motor brands.

I reviewed the majority of them here – 

There are many things that go into setting up a rig whether it’s for Duck Hunting, Fishing, Alligator Hunting, etc…

The main things are your boat size, engine size, and shaft size. That’s what we’ll cover in this article.

Jon Boat Size for Thai Longtial Mud Motor

Jon boat sizes can go from a 10 ft boat all the way up to 20 or 24 ft. Jon boats also have different widths to worry about too.

BUT in this article, a jon boat will be considered any aluminum boat that is riveted and easily accessible for purchase.

This narrows it down to a 1036 up to a 1542. Anything bigger than 15 ft long normally tends to be welded.

Boat size is a whole discussion of its own that will be covered later. For now, a single person can comfortably manage all jon boat sizes, two people would be best off in a 1436 or bigger, and then three people or more I would not recommend but could be done on a 1542.

So after you pick your boat, we’ll move onto engine size.

Engine Size for Thai Longtail Mud Motor

After choosing your boat size, take a ganger at that yellow sticker near the rear of the boat by the transom.

There will be a recommended HP (Horse-Power) rating for that boat. This is the maximum size engine that could be put on the boat safely.

This is also used to protect the integrity of the hull. If you put too much weight on the transom, it could buckle and fail.

FYI – I put a 13hp longtail on my 1436 jon boat rated for a 15hp engine and it weakened the transom. I contacted Alumicraft about it and they said they would not warranty it because I voided my warranty by installing a mud motor on it. So… keep that in mind whether you go with a different brand or report your issue differently.

So, engine size. In short: I would go with a Predator Engine from Harbor Freight. They are the most affordable and the easiest accessible engine there is for single cylinder engines.

If the engine runs without issue for the first ten hours, it’s golden. If you experience any issues within the first ten hours, exchange it for a new engine and try again.

Once you get into V-Twin engines, then you can do the 22hp Predator Engine or spend a little more money and get a Vanguard Briggs Engine which is some of the best engines out right now and doesn’t break the bank.

Harbor Freight Engines

  • Rated for 5hp or less = The 3hp Predator Engine is your best bet unless you want to pay a lot more for a Honda Engine. You may also be able to fit a 6.5hp engine on it depending on the boat size and reinforcement. Check the yellow sticker and see what other people have done.
  • Rated for 10hp or less = You have the option of a 6.5hp 212cc engine and an 8hp 301cc engine.
    • The 6.5hp is VERY popular. Lots of replacement and upgradable parts along with A LOT of people who have them so you can fix an issue pretty quickly.
    • The 8hp 301cc engine is not that popular and I would not recommend it unless in a unique situation.
    • Unique situation: you can’t fit a 13hp engine on your boat but you need to power through mud and vegetation. The 6.5hp engine can go through some stuff, but it lacks the torque to really power through. The 8hp gives you that extra torque you need.
  • Rated for 15hp or less = The main option is the 13hp 420cc engine. If you have EXTRA money, you could spend a lot more on the 13hp V-twin Vanguard Briggs engine. I’ve heard it is a sweet running engine.
    • Most people go with the 13hp Predator engine. I would say it is the MOST POPULAR engine on the market. This means issues can be fixed easily with the help of a large community and parts are easily accessible whether for replacement or upgrading. This 13hp is best paired with a 1436 and is the best setup in my eyes. 60349 is the Hemi version if you can find it
  • Rated 20hp or less = I haven’t found a jon boat with this rating. It’s either had a 15 HP Max rating or a 25 HP Max rating. You could probably squeeze the 22hp Predator on a boat with this rating but check with others to see if any issues came up. You could also do a 16hp or 18hp V-twin Vanguard Engine.
  • Rated 25hp or less = The 22hp Predator is the go-to engine for this setup. It is the least expensive and easily accessible. You also have the Vanguard engines which I see a lot more people using and they seem to really be gaining popularity. It’s just hard finding information on them with all the different variants and attachments you can order on them.

Shaft Length for Thai Longtail Mud Motors

Let’s keep it simple for shaft lengths when it comes to Thai longtails.

Use the shaft length that comes with the kit. Simple.

Some kits give you an option, like the Swamp Runner kits. The option is normally an 85″ shaft or a 100″ shaft. So let’s go over the differences;

  • 75″ shaft – good for small engine and small boat. Only available with mini kits (3hp engine)
  • 85″ shaft – good for boats up to and including 40″ wide that go less than 19mph. So if you have a 1440 going 18mph the 85″ should be good. This would be paired with engines up to and including the 13hp engine.
  • 100″ shaft – recommended on boats that have a bottom width of 41″ up to and including 48″ wide. Good for any speed.


  1. 1436 jon boat, 13hp engine, going 20mph = 100″ shaft
  2. 1436 jon boat, 13hp engine, reached 20 mph but normal load and use of the boat is around 15 to 18 mph = 85″ shaft
  3. 1436 jon boat (light-weight-version), upgraded 6.5hp engine + performance prop, possibility of 20mph = 100″ shaft
  4. 1436 jon boat (light-weight-version), upgraded 13hp engine, will definitely reach 20 mph = 100″ shaft for sure
  5. 1436 jon boat (light-weight-version), 13 hp engine, 20 mph, but you hunt heavy timber and need mobility = 85″ would be easier to move but could also do the 100″ shaft if you wanted too.

So… If you plan on going fast for long periods of time, the 100″ shaft will give you move reach and tail weight which will help keep the prop in the water and will be easier to control.

If you are going to be at idle speed or off plane for long durations, then the 85″ will be easier to handle and maneuver.

My Ideal Jon Boat Setup

THEE Best Solo Single Person Boat Setup:

  • 1436 Tracker Jon Boat {160lbs}
  • 13hp Predator Engine {76lbs}
  • Medium Swamp Runner Kit {57lbs} 85″ or 100″ shaft depending on the purpose.
  • Battery, trolling motor, fishing supplies, cooler, anchor, etc… = {~100lbs}

Total weight = 393-lbs +150-lbs {my weight} = 543-lbs

This setup is super lightweight, and something I can move by myself. On dry land it is tough, but on grass, muddy water slurry, pushing over sand bars, I can do it by myself. The Wetlander Slick Bottom Coating really helps out too. You could also add a winch onto this and guarantee you never get stuck again.

The 6.5hp engine doesn’t have the torque to push you through grass or mud and the 22hp is just too heavy.

The 1236 jon boat has the same footprint of a 1436 jon boat so it doesn’t hurt to get that extra two feet which seems to make a huge difference when two people are in the boat.

A 1542 gets wider and longer and the footprint changes in the water where you need the 22hp to push it so it gets too big and heavy for a single person to handle if you get stuck.

Longtail Mud Motor Sizing Conclusion

Thai longtails are great mud motors, but you need to know your options and what you are going to use them for.

There are PLENTY of people out there with these rigs. Find someone who has a similar rig you want and ask them if it does what you need it to do. If it does, build out your rig and skip over all the issues they already figured out for you.

A great place for this is the Longtail Facebook Group Over 2,000 people with longtail experience.

If you have any questions, ask them on the facebook group, use the contact form on here, comment on a JTG YouTube video, or ask a longtail mud motor brand.

Other than that, I hope your enjoy your Thai longtail mud motor and that you are able to decide on the proper size jon boat, engine size, and shaft length for your setup.

Untill next time, this is JTgatoring

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